Hi TMayall,

I've not seen many 1990 240 turbos.

I would check the small wire terminals at the coil for corrosion or looseness. It may not be your problem, but it was mine once, and it's easy to eliminate it as a potential source.

Someone will correct me if I'm wrong, but I think that you can verify power is getting through the 25 amp fuse, the relay and ECU by checking the orange wire at the AMM. If you carry a test light with you and it stalls, or wont start, pull back the rubber boot at the AMM connector. There should be power between that wire and ground with the key on. I think most people would do this only after a simple spark test came out negative, but that's up to you.

regards, Peter